"""Test correct operation of the print function. | |
""" | |
# In 2.6, this gives us the behavior we want. In 3.0, it has | |
# no function, but it still must parse correctly. | |
from __future__ import print_function | |
import unittest | |
from test import test_support | |
from StringIO import StringIO | |
NotDefined = object() | |
# A dispatch table all 8 combinations of providing | |
# sep, end, and file | |
# I use this machinery so that I'm not just passing default | |
# values to print, I'm either passing or not passing in the | |
# arguments | |
dispatch = { | |
(False, False, False): | |
lambda args, sep, end, file: print(*args), | |
(False, False, True): | |
lambda args, sep, end, file: print(file=file, *args), | |
(False, True, False): | |
lambda args, sep, end, file: print(end=end, *args), | |
(False, True, True): | |
lambda args, sep, end, file: print(end=end, file=file, *args), | |
(True, False, False): | |
lambda args, sep, end, file: print(sep=sep, *args), | |
(True, False, True): | |
lambda args, sep, end, file: print(sep=sep, file=file, *args), | |
(True, True, False): | |
lambda args, sep, end, file: print(sep=sep, end=end, *args), | |
(True, True, True): | |
lambda args, sep, end, file: print(sep=sep, end=end, file=file, *args), | |
} | |
# Class used to test __str__ and print | |
class ClassWith__str__: | |
def __init__(self, x): | |
self.x = x | |
def __str__(self): | |
return self.x | |
class TestPrint(unittest.TestCase): | |
def check(self, expected, args, | |
sep=NotDefined, end=NotDefined, file=NotDefined): | |
# Capture sys.stdout in a StringIO. Call print with args, | |
# and with sep, end, and file, if they're defined. Result | |
# must match expected. | |
# Look up the actual function to call, based on if sep, end, and file | |
# are defined | |
fn = dispatch[(sep is not NotDefined, | |
end is not NotDefined, | |
file is not NotDefined)] | |
with test_support.captured_stdout() as t: | |
fn(args, sep, end, file) | |
self.assertEqual(t.getvalue(), expected) | |
def test_print(self): | |
def x(expected, args, sep=NotDefined, end=NotDefined): | |
# Run the test 2 ways: not using file, and using | |
# file directed to a StringIO | |
self.check(expected, args, sep=sep, end=end) | |
# When writing to a file, stdout is expected to be empty | |
o = StringIO() | |
self.check('', args, sep=sep, end=end, file=o) | |
# And o will contain the expected output | |
self.assertEqual(o.getvalue(), expected) | |
x('\n', ()) | |
x('a\n', ('a',)) | |
x('None\n', (None,)) | |
x('1 2\n', (1, 2)) | |
x('1 2\n', (1, ' ', 2)) | |
x('1*2\n', (1, 2), sep='*') | |
x('1 s', (1, 's'), end='') | |
x('a\nb\n', ('a', 'b'), sep='\n') | |
x('1.01', (1.0, 1), sep='', end='') | |
x('1*a*1.3+', (1, 'a', 1.3), sep='*', end='+') | |
x('a\n\nb\n', ('a\n', 'b'), sep='\n') | |
x('\0+ +\0\n', ('\0', ' ', '\0'), sep='+') | |
x('a\n b\n', ('a\n', 'b')) | |
x('a\n b\n', ('a\n', 'b'), sep=None) | |
x('a\n b\n', ('a\n', 'b'), end=None) | |
x('a\n b\n', ('a\n', 'b'), sep=None, end=None) | |
x('*\n', (ClassWith__str__('*'),)) | |
x('abc 1\n', (ClassWith__str__('abc'), 1)) | |
# 2.x unicode tests | |
x(u'1 2\n', ('1', u'2')) | |
x(u'u\1234\n', (u'u\1234',)) | |
x(u' abc 1\n', (' ', ClassWith__str__(u'abc'), 1)) | |
# errors | |
self.assertRaises(TypeError, print, '', sep=3) | |
self.assertRaises(TypeError, print, '', end=3) | |
self.assertRaises(AttributeError, print, '', file='') | |
def test_mixed_args(self): | |
# If an unicode arg is passed, sep and end should be unicode, too. | |
class Recorder(object): | |
def __init__(self, must_be_unicode): | |
self.buf = [] | |
self.force_unicode = must_be_unicode | |
def write(self, what): | |
if self.force_unicode and not isinstance(what, unicode): | |
raise AssertionError("{0!r} is not unicode".format(what)) | |
self.buf.append(what) | |
buf = Recorder(True) | |
print(u'hi', file=buf) | |
self.assertEqual(u''.join(buf.buf), 'hi\n') | |
del buf.buf[:] | |
print(u'hi', u'nothing', file=buf) | |
self.assertEqual(u''.join(buf.buf), 'hi nothing\n') | |
buf = Recorder(False) | |
print('hi', 'bye', end=u'\n', file=buf) | |
self.assertIsInstance(buf.buf[1], unicode) | |
self.assertIsInstance(buf.buf[3], unicode) | |
del buf.buf[:] | |
print(sep=u'x', file=buf) | |
self.assertIsInstance(buf.buf[-1], unicode) | |
def test_main(): | |
test_support.run_unittest(TestPrint) | |
if __name__ == "__main__": | |
test_main() |